Toxicity is relative and varies by type.....
You can see 5 references on wood toxicity compiled here:
http://rwallace.public.iastate.edu/WTlinks.html#Processing-Toxic-Woods
It seems that most web sites I've referenced on this topic continually recycle the same information. I am slowly working on a revised and improved list with more botanical information and if possible medical references (via PubMed) on aspects of wood toxicity. However, getting actual documented references on toxicological and immunological data is quite difficult and in most cases, elusive.
The distinction must be made between health effects created by particulate respiratory insult, separate from those chemical toxins that can elicit responses like contact dermatitis. All fine particulates could be considered "toxic" if allowed to be inhaled and breathed-in all the way to the smallest alveoli.... there are many industrial standards out there for equipment to protect against air-suspended wood particulates, from whatever species.
Chemical compounds found in the wood which interact with body tissues that elicit a physical reaction in response to a direct chemical insult are truly toxic, and are found in various species. These can be through direct contact with wood or dust, or through volatilized compounds resulting from heating or cutting processes. For example, compounds found in the true rosewoods (genus
Dalbergia; family Fabaceae) which are sensitizing quinones, a class of neoflavanoids called dalbergiones can be considered chemically toxic, or the well-known compounds found in some species in the cashew family (Anacardiaceae) including poison ivy and poison oak (containing urushiol). These are "actual" (chemically) toxic species.
Another class of 'toxins' are the proteins associated with things like spalted wood - fungal proteins. While these in themselves are not directly toxic
per se (in the sense of a chemical poison, or the highly toxic aflatoxins), they can easily sensitize individuals to elicit immune responses of different degrees. Some of these responses can be mild, or can include the very serious and extreme condition of anaphylaxis. This 'toxicity' is dependent on the individual's immune system, and is often developed through sensitization over time.
Thus, toxicity is relative, and (in my opinion) there has not yet been a good compilation of this information presented from documented sources that can be used as a single good reference. The safe thing to do is consider all wood species "toxic" until documented or proven otherwise. Although dried hard maple is not likely to be chemically or immunologically toxic (we use it for cooking utensils and cutting boards), inhaling fine maple dust can elicit responses from the body that still are considered a physical respiratory insult, and can contribute to long-term health problems.
Question - I'd like to know if this would be a good topic to write an article on for
American Woodturner.... would people read such an article, even if the "technical" information would be included?
I hope this helps folks understand the topic of 'wood toxicity' a little better....
(Prof.) Rob Wallace
